In HDD Smart summary, the QNAP reports, "HDD I/O Status Abnormal". A "quick test" completed without finding any errors. A "full test" is running but incomplete. A copy of the dmesg from an SSH session into the QNAP is below.

The disks in the NAS (and the NAS itself) are only 10 months old. They are Hitachi Ultrastars (with 5 year warranties) and appear on the compatibility list. I ran the QNAP "complete test" and it reported, "Status: Test completed and no errors found". There are no new errors in dmesg. So if I return this drive, is this dmesg alone enough to prove there is a problem? I don't want to lose redundancy (it's RAID 5) to return a drive that will be returned to me as no fault found. Is there some other test that can be run which will demonstrate a fault with the drive, as the quick test and complete test have failed to identify any issues?

QNAP does't sell hard drives, if you bought QNAP w/ hard drives inside, it should be bounded by re-seller or distributor.

They are Hitachi Ultrastars (with 5 year warranties) and appear on the compatibility list

I believe it is under compatibility list, however, please give me the hard drive model#, so I can double check for you.

I ran the QNAP "complete test" and it reported, "Status: Test completed and no errors found" In HDD Smart summary, the QNAP reports, "HDD I/O Status Abnormal" s there some other test that can be run which will demonstrate a fault with the drive

As you described, SMART has shown "abnormal" on QNAP web interface, however the SMART exam result actually is from the firmware of hard drive,which is from Hitachi hard drive firmware. Of course, you can go to Hitachi's website to download their diagnose software, connect drive 4 on your PC and run "detail diagnose".Using this method, you can get more accurate result than SMART.

Additional information, if you go to [Control Panel], [Storage manager], and physical disks, choose hard drive 4 and run [scan now].It may show bad block information.

I don't want to lose redundancy (it's RAID 5) to return a drive that will be returned to me as no fault found

If I were you, I will backup my data first, then I will not worried about losing RAID5 redundancy during hard drive replacement window.

As you described, SMART has shown "abnormal" on QNAP web interface, however the SMART exam result actually is from the firmware of hard drive, which is from Hitachi hard drive firmware.

What's puzzling is the smartctl result above does not show any errors either. I would have imagined whatever QNAP's web admin GUI is saying is coming from the drive's SMART feature, but it doesn't seem to be. The only two indications of a problem are the dmesg log posted earlier and the web admin GUI telling me "HDD I/O Status Abnormal". No quick test, full test, smartctl or new dmesg indicates an issue.

Of course, you can go to Hitachi's website to download their diagnose software, connect drive 4 on your PC and run "detail diagnose". Using this method, you can get more accurate result than SMART.

Only problem with that is I don't have Windows, and I don't have a workstation with a 6 GB/sec SATA interface in any event (only 3 GB). I am also reluctant to knowingly eliminate redundancy (by removing the drive from a production QNAP) just to run a test of a drive that doesn't seem to be that critical. Are there any commands or packages I can install on the QNAP to investigate this further? Past experience tells me if I ship this drive back to Hitachi without hard evidence of a problem, they'll just send it back to me with "no fault found" -- especially given I can't find a fault locally with any commands.

If I were you, I will backup my data first, then I will not worried about losing RAID5 redundancy during hard drive replacement window.

I have ongoing backups of important data with ElephantDrive (great interop with the QNAP BTW). I'd hate to see how long it takes to restore many hundreds of gigabytes over an Internet connection though!

Is there anything else I can try on the QNAP itself? Are you sure an I/O error is indeed a drive problem as opposed to a SATA interface issue? I read a few comments elsewhere that suggested I/O errors could be a faulty cable or connector. Does this seem plausible given what we're seeing here with no SMART errors?

The only two indications of a problem are the dmesg log posted earlier and the web admin GUI telling me "HDD I/O Status Abnormal" Are there any commands or packages I can install on the QNAP to investigate this further?

You have 316 bad blocks there and triggered an attempt to reallocate them 427 times. The disk is sure like ** faulty and to be replaced! It absolutely does not matter that they are "only 10 months old". RMA it!

Yes. I followed the first Google result for "smartmon tutorial" and it pointed me to the lines of my output which said, "SMART overall-health self-assessment test result: PASSED". Unfortunately I didn't read the lines you identified.

doktornotor wrote:You have 316 bad blocks there and triggered an attempt to reallocate them 427 times. The disk is sure like ** faulty and to be replaced! It absolutely does not matter that they are "only 10 months old". RMA it!

I am on firmware 3.8.3 Build 20130426. I have looked through the web admin interface but cannot find a Control Panel. Is it somewhere else? Apologies in advance if I am overlooking something really obvious.